Polyester resins and method of making same



United States Patent Ofitice 3,376,271 Patented Apr. 2, 1968 3,376,271POLYESTER RESINS AND METHQD OF MAKING SAME John E. Masters and Darrelll). Hicks, Louisville, Ky., assignors to Celanese Coatings Company, acorporation of Delaware N Drawing. Continuation-impart of applicationSer. No. 415,782, Dec. 3, 1964. This application Sept. 20, 1965, Ser.No. 488,726 The portion of the term of the patent subsequent to May 14,1980, has been disclairned 11 Claims. (Cl. 260-784) This application isa continuation-in-part of my continuation-in-part and copendin'gapplications Ser. Nos. 415,782 and 415,194, filed Dec. 3, 1964, and Dec.1, 1964, respectively, which are continuations-in-part of my applicationSer. No. 80,973, filed Jan. 6, 1963 all of the above applications arenow abandoned. This latter application is a division of my applicationSer. No. 594,716, filed June 29, 1956, now "Patent No. 3,089,863.

The invention relates to new synthetic resins of the polyester type. Inone of its aspects the invention pertains to a new class of branchedchain polyester thermoplastic resins. In another of its aspects theinvention provides a process for preparing novel polyesters of extremelyhigh molecular weight having utility in the textile field. In accordancewith still another of its aspects the invention provides a method forthe preparation of unsaturated polyesters which can be cured by knownmethods to produce useful potting, casting, molding and laminatingcompositions.

Conventionally, polyesters are formed by condensing dibasic acids ortheir anhydrides with polyhydric alcohols under esteri-ficationconditions, that is,conditions whereby there is a liberation of water.'By these known processes, when the functionalities of the acid and ofthe alcohol do not exceed two, thermoplastic resins result. Theseresins, however, are not multi-branched chain compositions. Branchedchain, thermoplastic resins can be made by the use of compounds havingfunctionalities greater than two, if these compounds are used in smallproportions. However, when reactants having functionalities greater thantwo are used, functional groups are free to react with each other. Underreaction conditions generally employed, functional groups tend to reactwith each other to form three dimensional or cross-linked structures,making it very difiicult to produce thermoplastic non-crosslinked resinshaving a plurality of branch chains. It is also diificult, if notimpossible, to make high molecular weight thermoplastic polyesters. Toform thermoplastic resins from polyfunctional reactants, the productgenerally must be modified by monofunctional chain stoppers to preventfunctional groups from forming three dimensional structures. Hence,highly branched chain, noncross-linked polyesters of high molecularweight are virtually unknown.

In accordance with this invention, however, branched chain,thermoplastic polyester resins having extremely high molecular weightscan be prepared. By this invention, a new class of polyester polymers isprovided, each polyester having a multiplicity of linearnon-cross-linked polyester branch chains.

In the practice of this invention, rather than reacting a polycarboxylicacid solely with a polyfunctional alcohol, difunctional polymer-formingreactants are combined in the presence of a polyfunctionalnucleus-forming compound. The difunctional polymer-forming reactants aredibasic acid anhydrides and monoepoxides. A dibasic acid anhydride and amonoepoxide, if pure, will not react. A dibasic acid anhydride will,however, react with an alcoholic hydroxyl group even at relatively lowtemperatures to form the half-ester. A monoepoxide, on the other hand,reacts more readily at low temperatures with carboxyl groups than withhydroxyl groups. Both the reaction between an anhydride and a hydroxyl,and the reaction between a monoepoxide and a carboxyl take place at atemperature below a normal esterification temperature. Since anhydridesand monoepoxides will not react with each other, it is necessary toinitiate the reaction with a group reactive with the monoepoxide to forma hydroxyl group which in turn will react with the anhydride; or aninitiator which will react with the anhydride to form the half-esterthus providing a carboxyl group for reaction with the monoepoxide. Orthe initiator may be reactive with both an anhydride and a monoepoxide.

These novel products of this invention are formulated by reactingtogether the initiator having at least three functional constituentswhich comprise of carboxyl radicals, phenolic radicals, or combinationsthereof, or combinations thereof with alcoholic hydroxyl radicals, inthe presence of a dibasic anhydride and monoepoxide. Depending upon theinitiator used, the reaction takes place alternately with the dibasicanhydride and the monoepoxide to form the thermoplastic branch chainpolyesters. It is understood that this invention may contemplate theproduction of first a polymer or copolymer of the initiator and thenreacting the polymer or copolymer with alternately either the dibasicanhydride and the monoepoxide, or vice versa, to formulate branch chainsof a monomer or polymer nature onto the polymer or copolymer chain,depending upon the proportions of the monoepoxide or dibasic anhydrideutilized.

When the monoepoxide and the dibasic acid anhydride are reacted with aphenol, the reaction takes place between the phenolic hydroxyl group andthe monoepoxide to form an ether as illustrated in Equation A using atrihydric phenol and propylene oxide as an example:

the phenolic group is acidic and the reaction between an acid anhydrideand the phenolic group can be reached with dilficulty but when theepoxide group is also present, this readily reacts first with thehydroxyl group to produce the type of structure illustrated in EquationA. The acid anhydride will then react with the alcoholic hydroxyl groupproduced in the side chain by reason of the reaction between the phenoland the monoepoxidc to form an ester linkage as illustrated in EquationB:

If the phenol is trihydric and the reaction is carried out with threemols of the monoepoxide and three mols of the anhydride, the polyesterproduced will have terminal carboxylic acid groups as shown in EquationB. The use of excess monoepoxide will result in one or more side chainsbeing terminated by an alcoholic hydroxyl group 3 as illustrated inEquation C: (C) H O O H I II It I OCHzC-OC OCHz-C|3OH H; CH3

Thus, if six mols of monoepoxide are used with three mols of ananhydride with a trihydric phenol, all three side chains will terminatewith alcoholic hydroxyl groups.

The molar ratio of the monoepoxide and anhydride to the functionality ofthe phenol can be varied quite widely producing polyester side chainshaving as many as 100 or more recurring units.

The same reaction would take place with polyhydric phenols containingthree or more phenolic hydroxyl groups such as contained in theconventional Novolak resins. The length of the polyester side chain willdepend somewhat upon the molecular weight of the starting polyhydricphenol. The only determining factor on the length of the polyester sidechain would be gelation.

When the monoepoxide and the dib-asic anhydride are reacted with amonomer or a polymer having carboxyl radicals, the reaction proceeds ina very similar fashion to that illustrated above with respect to thereaction of phenol with a monoepoxide and a dibasic anhydride. That is,the reaction proceeds first between the carboxyl functional groups ofthe carboxyl radicals and the monoepoxide. Using as an example propyleneoxide and a carboxyl compound being the reaction product of vinyltoluene and acrylic acid, a reaction would take place resulting in theproduct illustrated in Equation D:

(D) O H H--ilOOHr-d-OH I Hi The hydroxyl groups of the resulting productthen readily react with the dibasic anhydride, as for example phthalicanhydride, to form the polyester linkage as illustrated in Equation E:

COOH

It must also be understood that if an equal mol ratio of monoepoxide anddibasic anhydride is used, the resulting polyester will have terminalcarboxyl groups. However, if an excess monoepoxide is used, the productwill result having terminal hydroxyl groups as evidenced by equation F:

coon I I The carboxyl groups of the product illustrated in equation (G)then react with a oxide, to form the product illustrated in Equation H:

in excess, either carboxyl or alcoholic hydroxyl groups I may appear inthe terminating positions.

For the purpose of producing coating compounds, we

prefer to have alternate epoxide and anhydride units or moieties of atleast three present in one product.

The maximum number of units of epoxides or anhydrides which can bepresent in a compound will vary widely and depend greatly upon the,amount of initiator. I

used. However, the maximum number of units will be that which willproduce a product which is thermoplastic. It is, of course, to beunderstood that the length of the polyester side chain will bedetermined by gelation.

With respect to an acrylic compound, wherein the compound carries abackbone which is an acrylic polymer or copolymer, it is again preferred.to have at least three to five epoxide or anhydride units, orcombinations thereof, present.

Thus, it can be seen that anhydride and monoepoxide monomers addalternately to the initiator, forming branch chains. The initiator is acompound which will react with a monoepoxide and/ or a dibasic acidanhydride to form either hydroxyl groups for reaction with anhydride orcarboxyl groups for reaction with monoepoxide, in other words a compoundcontaining active hydrogens. It is noted that the terminal groups of themolecule cannot react with each other or with terminal groups of otherresin molecules. The terminal groups of the molecule can only react withunreacted epoxide or anhydride, depending upon whether or not thetermnial. group is a hydroxyl or carboxyl groupplf an excess of eithermonoepoxide or of dibasic acid anhydride is used, the molecule willterminate. A hydroxyl terminated compound is formed if the monoepoxideis in excess and a carboxyl terminated compound is formed it theanhydride is in excess. If equimolecular quantities monoepoxide are usedcarboxyl and hydroxyl terminal groups. Since the monoepoxide and dibasicacid anhydride do not readily react with each other, and since either orboth must first react with a third compound, it is seen that thiscompound functions as a reaction center from which branches emanate byalternate monomeric additions of dibasic acid anhydride and monoepoxide.The initiator thus functions as a reaction center from which a number oflinear polyester, polymeric chains emanate, the number of chains beingequal to the functionality. of the initator.

Among the new products contemplated by the invention included aremonomers, polymers or copolymers having at least three carboxyl orphenolic groups, or combinations thereof, or combinations with alcoholichydroxyl groups in which at least three of the terminal.

or combinations thereof,

monoepoxide such a propylene of dib-asic acid anhydride and i themolecule will contain both where (a) A=CH2-CH where R :H, an alkylradical, an alkenyl radical,

0 oH2oi:-Rz

or -CH O-R where R =an alkyl, alkenyl or aryl radical,

(b) Y=nucleus of a dibasic acid anhydride and (c) x=at least 1.

In accordance with an embodiment of this invention, therefore,dicarboxylic acid anhydrides and monoepoxides are utilized aspolymer-forming reactants, the reaction being initiated by an initiator,to which the polymer-forming reactants are joined to form branch chains.As the initator, it is desirable to employ polyfunctional compoundscontaining active hydrogens whereby said initiator is capable ofreacting with an epoxide or an anhydride or both. In other words, theinitiator will be an acid, an alcohol, or a phenol, each having afunctionality of at least three, or a polyfunctional compound such as acopolymer, an ester or an ether having carboxyl-substituents, and/orphenolic hydroxyl or alcoholic hydroxyl substituents.

Examples of such initiators containing phenol groups are trihydricphenols such as phloroglucinol, 1,2,4- trihydroxybenzene,1,2,3-trihydroxybenzene and tetra (hydroxyphenyl) alkanes or Novolakresins which are the reaction products of aldehydes and phenols(including phenol, substituted phenol, resorcinol, etc.).

Example of polybasic acids which act as initiators are trimellitic acid,tricarballylic acid, aconitic acid, trimesic acid and pyromellitic acid.Other carboxyl containing initiators may include resin-maleic or fumaricadducts, and maleinized or fumarized oils.

Also included are polymers and copolymers containing a large number ofcarboxyl groups, for example vinyl carboxylic acid polymers andcopolymers such as the copolymers of vinyl toluene and acrylic acid, orcopolymers of vinyl acetate and crotonic acid, acrylic acid,methylacrylic acid, itaconic acid, maleic acid, fumaric acid, etc. Thesecopolymers have as many as 100 carboxyl groups per linear chain and fromsuch copolymers a wide variety of novel resinous compositions can beprepared having branch chains equal to the number of carboxyl groups perlinear chain of the copolymer.

The carboxy copolymers can be formed by free radical polymerization ofan unsaturated carboxylic acid including acrylic, methacrylic andcrotonic acid, half-ester of maleic acid, etc., with anothermonoethylenically unsaturated monomer polymerizable therewith.

Examples of monoethylenically unsaturated monomer which can bepolymerized with the unsaturated carboxylic acids include acrylonitrile,methacrylonitrile, acrylic and methacrylic acids, their esters, amidesand salts, itaconic acid and its functional derivatives, particularlyits esters, maleic anhydride or maleic and fumaric acids and theiresters, vinyl esters and esters, vinyl sulfides, styrene, vinyl toluene,and allyl esters of monocarboxylic acids. Specific vinylidene compoundsare methyl, ethyl, isopropyl, butyl, tert-butyl, octyl, dodecyl,octadecyl, octenyl, or oleyl acrylates or methacrylates or itaconates,dimethyl maleate or fumarate, diethyl maleate, diethyl fumarate, diethylcitraconate, diethyl chloromaleate, tert-butylaminoethyl acrylate ormethacrylate, acrylamide, methacrylamide, N-methacrylamide,N-butylmethacrylamide, hydroxyethyl vinyl ether, octyl vinyl ether,dodecyl vinyl ether, ureidoethyl vinyl ether, ureidoisobutyl vinylether, ethyl vinyl ether, butyl vinyl ether, butyl vinyl sulfide, methylvinyl sulfide, dodecyl vinyl sulfide, vinyl acetate, vinyl propionate,vinyl laurate, vinylidene chloride, vinyl chloride, methylolacrylamide,

,B-hydroxyethyl acrylate, isobutylene, a-methylstyrene, p-methylstyrene,p-chlorostyrene, vinylnaphthalene, etc., which may be used.

Polyfunctional alcohols having at least three alcoholic hydroxyl groups,for example, erythritol, pentaerythritol, castor oil andpolypentaerythritol, e.g., dipentaerythritol, tripentaerythritol,trimethylolethane, trimethylolprop-ane, sorbitol, mannitol, arabitol,adonitol, xylitol, persitol, ricinoleic esters and partial esters of theabove listed polyols, allyl alcohol copolymers such as copolymers ofstyrene and allyl alcohol, polyvinyl alcohol, defunctionalizedpolyepoxide (the reaction of 4 (n) epichlorohydrin, 5 (n+1) diphenolsand 2 ethylene chlorohydrins), polyepoxide resins partially esterifiedwith monobasic acids leaving three or more hydroxyl groups, polymers andcopolymers of hydroxyalkyl esters of polymerizable acids such ashydroxyethyl acrylate, hydroxypropyl methacrylate, hydroxybutylcrotonate, hydroxypropyl maleate, dihydroxy-propyl fumarate, etc., andtripentaerythritol may also be used as initiators along with allylalcohol polymers and copolymers.

This invention also contemplates initiators having phenolic hydroxyl andalcoholic hydroxyl groups, for example, partial hydroxy-alkylatedphenols such as the reaction products of one or two mols of ethyleneoxide, propy=lene oxide, butylene oxide, or styrene oxide reacted withphloroglucinol, Novolak resins partially etherified with monoepoxides ormonochlorohydrins or a bisphenol terminated bisphenol-epihalohydrincondensate can be used which is prepared by reacting, in aqueous medium,n mols of the epihalohydrin with n+1 mols of bisphenol using n mols ofan alkali (plus 10 percent molar excess), for example, sodium,potassium, or calcium hydroxide. This reaction is usually carried out byadding the halohydrin to the mixture of bisphenol, alkali, and water atabout 50 C., raising the temperature to C. The polymer thus formed issubsequently washed after neutralizing the Water medium with HCl or H POThe product is a linear polyether polymer terminated with bisphenol andcontaining intermediate alcoholic hydroxyl groups. The terminal hydroxylgroups, i.e., those attached to the terminal bisphenol groups, arephenolic hydroxyls.

Another group of initiators within the contemplation of this inventionincludes compounds having both carboxyl and alcoholic hydroxylsubstituents, for example the hydroxy-carboxy copolymers disclosed in mycopending application Ser. No. 364,274, filed May 1, 1964. Further, someof the carboxyl groups, but not all, of a vinyl toluene-acrylic acidcopolymer can be reacted with a monoepoxide to form a carboxy-hydroxyinitiator. Other alcoholic hydroxyl and carboxyl-containing initiatorsmay be maleinized and fumarized epoxy esters containing hydroxyl groups,epoxy resins terminated with polybasic acids, alkyd resins, glycericacid, gluconic acid, maleic acid, tartronic acid, tartaric acid,resorcylic acid, citric acid, and dimethylol propionic acid. Further,there is contemplated by this invention polymeric substances havingalcoholic hydroxyl and acid containing groups such as h-ydroxy-carboxycopolymers of arabitol and trimellitic acid, epoxide resins partiallyesterified with unsaturated fattiy acids and further reacted with maleicor fumaric aci Still another group of initiators within thecontemplation of this invention cludes carboxyl-containing and phenolichydroxyl-containing compounds such as diphenolic acid, resorcylic acid,orsellinic acid, gallic acid and pyrogallol carboxylic acid. Also,bisphenol terminated bisphenol-epihalohydrin condensates made as setforth hereinbefore by reacting n moles of epihalohydrin with n+1 mols ofbisphenol in the presence of n mols of sodium hydroxide (plus 10 percentmolar excess) can be partially esterified with a dicarboxylic acid oranhydride to produce a compound containing phenolic hydroxyl radicals,carboxyl radicals, and, if desired, alcoholic hydroxyl radicals. Otherbisphenol-epihalohydrin condensates are also contemplated, for example,a polyhydroxy polyether condensate of bisphenol, epichlorohydrin, andethylene ehlorohydrin, containing six alcoholic hydroxyl groups.

Other examples of initiators having carboxy-l, alcoholic, hydroxyl andphenol groups may be the reaction product of diphenolic acid and anepoxide or the reaction product of a dibasic acid with an epoxide resinhaving terminating phenol groups, such as mono(hydroxyethyl)ether ofdiphenolic acid and mono(hydroxypropyl)ether of diphenolic acid, andepoxide resins terminated with polyphenols partially reacted with anhydrides or dibasic acids.

It is to be understood that the term polymer used herein may includecopolymers and interpolymers.

In the preparation of the polyester resins of this invention the threereactants are combined and reacted under such conditions that noformation of water takes place during the reaction. In other words, thereaction is conducted under sufliciently mild conditions, for example, atemperature sutficient to bring about the carboxyl-epoxide reaction, yetnot sufiiciently high to bring about a carboxylhydroxyl, oresterification, reaction which would result in the formation of water,generally a temperature not exceeding 150 C. Desirably the initiator,and the dibasic acid anhydride are combined and the monoepoxide isslowly added thereto. By this method the temperature can more readily becontrolled, since in most instances the reaction is exothermic,especially during its early stages. The temperature desirably ismaintained in the range of 115 C. to 130 C.

As. the polyester is formed there is a progressive reduction in acidnumber. In some instances, it is desirable to employ catalysts in theformation of branch chained polyesters. The selection of such catalystsmay be from those already well known and suitable for this purpose andinclude tertiary amines or those epoxy-carboxy catalysts as described inUS Patent 3,002,959 and any other catalysts as disclosed in applicationSer. No. 458,409, filed May 24, 1965.

Monoepoxides within the contemplation of this invention are epoxycompounds having three-membered epoxide rings and free of other reactivegroups, particularly groups capable of reacting with an acid anhydride.Included is oxirane, or ethylene oxide, as well as the alkyl oxiranes,for example, methyl oxirane or propylene oxide, butene-2-oxide, etc.Among others are ethers and esters containing only one three-memberedepoxide substituent, each free of other groups capable of reacting withan acid anhydride. Examples are phenyl glycidyl ether, isopropylglycidyl ether, glycidyl benzoate, butyl glycidyl ether, allyl glycidylether, glycidyl acrylate, a glycidyl methacrylate, glycidyl crotonate,glycidyl acetate, etc. With reference to unsaturated monoepoxide, somedegree of selection must be exercised. For instance, the use, in thepractice of this invention, of an unsaturated monoepoxide with anunsaturated dibasic acid anhydride results in the formation ofcross-linked thermosetting compositions. Since cured compositionsresult, the use of an unsaturated monoepoxide in conjunction with anunsaturated dibasic acid anhydride is not suggested in makingthermoplastic resins according to this invention. In other words, amonoepoxide containing a double bond such as allyl glycidyl ether, orglycidyl acrylate, desirably is not employed with an unsaturated acidanhydride, such as maleic acid anhydride. It is preferred to employ anunsaturated acid anhydride with a saturated monoepoxide.

Dicarboxylic acid anhydrides applicable to this invention include bothaliphatic and aromatic dicarboxylic acid anhydrides, either saturated orunsaturated, for example, succinic, adipic, maleic, glutaric, phthalic,isosuccinic, and sebacic anhydrides, naphthalene dicarboxylic acidanhydrides, etc. Endocisbicyclo (2,2,1) 5 heptene-2,3-dicarboxylicanhydride (sold under the trademark Nacid anhydride) and1,4,5,6,7,7-hexachlorobicyclo-(2,2,1)-5- heptene-2,3-dicarboxylicanhydride (sold under the trademark Chlorendic anhydride) are alsodesirable.

One of the advantages of this invention is that highly branched chainthermoplastic polyesters are prepared following the invention. It ahighly functional initiator is used according to the invention dibasicacid anhydride and monoepoxide add alternately through each reactivegroup to produce highly branched chain compounds. These.

branch chains do not cross-link as in conventional processes because inthis process esterification conditions are not employed. In priorprocesses now in use end groups react due to esterification. Inaccordance with this invention monomers add to the initiator to formbranch chains without the formation of water. For example, if a compoundhaving twelve or fifteen carboxyl or alcoholic hydroxyl radicals is usedas an initiator a polyester will be formed having twelve or fifteenbranch chains since the initiator becomes the nucleus from which thebranch chains emanate, the number of branch chains being equal to thefunctionality of the initiator. As a further example, ployesters havebeen prepared having one hundred or more branch chains. Thus, acopolymer of vinyl toluene and hydroxy propyl acrylate has been preparedby known polymerization methods to givea product having aboutone hundredalcoholic groups per linear chain.

Desirable polyesters have been prepared with hydroxy or carboxycopolymers as initiators by reacting propylene oxide and maleicanhydride in the presenceof those copolymers. It is understood that inthe preparation of these polyesters a modicum of initiator is used inproportion to the monoepoxide and dibasic acid anhydride since thefunction of the initiator is to serve as a nucleus from which the branchchains emanate. A very small amount of initiator is used if a highmolecular weight product is desired. And, as the amount of initiator ofnucleus-forming material is increased, the length of branch chains isdecreased. Thus, if dipentaerythritol were employed as the initiator andone mol of dipentaerythritol was employed with sixty mols of monoepoxideand sixty mols of dibasic acid anhydride on the average each branchchain in the linear polyester would contain twenty mols of monoepoxideand twenty mols of anhydride. However, if two mols of the initiator wereemployed, rather than one, each branch chain in the polyester wouldnormally contain ten mols of monoepoxide and only ten mols of dibasicacid anhydride. It is apparent then that the more initiator, the shorterthe branch chains will be. The ratio of reactants to initiator thereforedepends upon the desiredsize of the molecule and proportions are notcritical. The number of branch chains will be equal to the functionalityof the initiator and the length of each branch chain will beapproximately equal to the total number of mols of monoepoxide plus thetotal number of mols of anhydride per mol of the initiator compound,divided by the functionality of the initiator compound. In the light ofthese considera tions, the amount of monoepoxide and dibasic acid anhy-.

dride to be reacted in the presence of the initiator can readily bedetermined in each art. As a general statement, it

to 1:2 and the mol ratio of anhydride plus monoepoxide to the initiatoris greater than 7:1.

A feature of this invention is that unsaturated polyesters can beprepared which can be subsequently cured, for example, with vinylmonomers, to give desirable castings and pottings. These compositionswhich can be cured with a vinyl monomer, are made'by the use of anunsaturated dibasic acid anhydride or an unsaturated monoepoxide as areactant. The use of, say, maleic acid anhydride, results in thepresence of recurring double bonds in each branch chain. Double bonds ineach branchchain will also result from the use of an unsaturatedmonoepoxide. For example, allyl glycidyl other can be used. However, asindicated, it is undesirable to employ an unsaturated monoepoxide incombination with an unsaturated dibasic acid anhydride, for instance,allyl glycidyl ether in combination with maleic acid anhydride. Inaddition, coatings, castcase by one skilled in the.

can be said that the mol ratio of monoepoxide to anhydride is in therange of 2:1

ings and pottings can also be prepared by reacting both saturated orunsaturated polyesters of this invention with urea-formaldehyde resins.

An advantage of this invention is that polyesters can be prepared havingmolecular weights approximately equal to any desired molecular weight.The proportions of reactants to give a linear polyester of atheoreticalmolecular Weight can be calculated and when these proportions are used apolyester can be prepared which has a molecular weight which correspondsapproximately with the calculated theoretical molecular Weight. When aninitiator is used which is capable of reacting only with an organic acidanhydride, the following formula can be used to theoretically calculatethe molecular weight of the polyester which it is desired to prepare.

In this formula miwS represents the molecular weight of the initiator,mwA represents the molecular weight of the dibasic acid anhydride andmwE represents the molecular weight of the monoepoxide, mwP is thetheoretical molecular weight of the polyester, nA represents the numberof mols of anhydride, 1 represents the functionality of the initiator,and 2: represents the number of terminal hydroxy groups desired in thepolyester. From the equation and using a desired theoretical molecularweight of the polymer, the number of mols of anhydride can becalculated. The formula is based upon a ratio of initiator to anhydrideto epoxide of 1 to nA to nA- (f-z). The number of mols of epoxide,therefore, can be derived from nA-(fz) since nA, f and z will all beknown quantities. Referring again to z, when the initiator is capable ofreacting with an epoxide group and not an anhydride the formula is thesame but 2 represents the number of terminal carboxyl groups desired.

In carrying out this invention it is generally desirable to melt themixture of dibasic acid anhydride and initiator, to slowly add themonoepoxide, while heating the reaction mixture at a temperature of 120C. to 150 C. until there is no change in acid value. In many instances,acid values of from 1 to will be obtained, indicating substantiallycomplete reaction and a product approaching the theoretical. However, insome cases, as where polymeric nuclei having a functionality of over 100are used, acid values up to are usually obtained, especially Where veryhigh molecular weight products are being prepared. In the case of lowboiling monoepoxides rather than taking acid numbers it is convenient tojudge the reaction by the reflux. After all of the low boilingmonoepoxide has been added, the temperature is raised as reflux'permits,to approximately 150 C. and this temperature is maintained until refluxceases, indicating that monoepoxide has been consumed. If a higherboiling monoepoxide, is employed, that is, one having a boiling pointabove 140 C. to 150 C., no reflux will be observed.

For a furtherunderstanding of the invention, reference is made to thefollowing specific examples, the viscosities given being Gardner-Holdtviscosities run at C. These examples are intended to be illustrative ofthe invention only, since different embodiments can be made withoutdeparting from this invention.

Example 1 To prepare a branched chain thermoplastic polyester havingfour branch chains and a theoretical molecular weight of 5928, propyleneoxide, pentaerythritol, maleic anhydride, and phthalic anhydride areemployed in a mol ratio of 11 /2 to A to 4 to 4. The pentaerythritol(24.1 grams), maleic acid anhydride (279.1 grams), phthalic acidanhydride (421.5 grams), and propylene oxide (475.0 grams) are heatedtogether in a two liter, three neck, round bottom flask provided with astirrer, thermometer, dropping funnel and a Dry Ice condenser. When thetemperature in the reaction vessel reached 120 C. to 125 C., propyleneoxide was added through the dropping funnel to the flask contents at arate sufiicient to maintain a heavy reflux at a temperature of C. Thedrop-wise addition of the propylene oxide requires approximately 15hours. When all the propylene oxide is added and the reflux diminishes,the temperature of the flask contents is raised to C., as the refluxpermits and held at a temperature until the reflux ceases. The productis then heated and vacuum distilled for ten minutes at 2 mm. Hg. Thecontents of the resulting product are: acid value, 11; viscosity, Z-Z at66.7 percent solids in styrene; color, 4-5 at 66.7 percent solids instyrene.

Strength properties on the preceding product are determined on specimensmachined from sheet castings prepared by casting blends of thepolyester, with styrene, using a catalyst. The molds are made fnom two8" x 12" x Mi" glass plates wrapped with cellophone so that one side ofeach plate is free of wrinkles. These plates are then assembled, smoothside inward, into a mold by using 4" polyvinyl chloride-acetate plastictubing as a gasket on three of the four edges, and using six C-clamps tohold the two plates together. The clamps are tightened so as to form acavity between the glass plates. The resin solutions are poured into themold, while the latter is in a vertical position. The catalyst is apaste of fifty percent benzoyl peroxide, and fifty percent tricresylphosphate.

Styrene (120 grams) containing 500 p.p.m. tertiary butyl catechol, andthe product of this example grams) are blended together using heat toeffect solution. This solution is cooled to 25 C. to 30 C. and catalyst(six grams) is added. The resulting solution is poured into a mold ofthe type described above. The mold is placed upright in a 75 C. oven andallowed to remain one hour. The oven temperature is then raised to 121C. and the mold contents are held at this temperature for one hour. Themold contents are then removed from the oven, allowed to cool to 30 C.to 40 C., and the re sulting casting removed from between the glassplates. This casting is clear and very hard, having the followingstrength properties on the casting:

Tensile strength p.s.i 7700 Flexure strength p.s.i 17400 Impact strengthft. lb./ inch of notch 0.30 Alpha-hardness 1 11 Example 2 To prepare abranched chain thermoplastic polyester having four branch chains and atheoretical molecular weight of 4432, propylene oxide, pentaerythritol,maleic anhydride, and phthalic anhydride are employed in a mol ratio of11 to /2 to 4' to 4. The pentaerythritol (48.2 grams), maleic acidanhydride (278.3 grams), phthalic acid anhydride (420.2 grams), andpropylene oxide (453.0 grams) are reacted together in a manner describedin Example 1. The addition of the propylene oxide requires approximatelythirteen hours. The product is then taken to 150 C., held until refluxceases, and vacuum distilled for ten minutes at 2 mm. g. Constants foundon the product are as follows: acid value, 11; viscosity, V-W at 66.7percent solids in styrene; color, 34 at 66.7 percent solids in styrene.

Styrene (120 grams) containing 500 p.p.m. tertiary butyl catechol, theproduct of this example (180 grams), and catalyst (six grams) areblended together and processed to-a cast sheet, using the procedure ofExample 1. The resulting casting is clear and rigid, having thefollowing strength properties:

Tensile strength p.s.i 6500 Flexure strength p.s.i 13500 Impact strengthft. lb./inch of notch. 0.25 Alpha-hardness 11 1 Example 3 In order toprepare a branched chain thermoplastic polyester having four branchchains and a theoretical molecular weight of 1584, propylene oxide,pentaerythritol, maleic anhydride and phthalic anhydride are employed ina mol ratio of 11 to 1 to 4 to 4. The pentaerythritol (92.8 grams),maleic acid anhydride (267.5 grams), phthalic acid anhydride (404.0grams) and propylene oxide (435.5 grams) are reacted together using theprocedure described in Example 1. The addition of the propylene oxiderequires approximately ten hours. After raising the temperature to 150C., and maintaining this temperature until reflux ceases, the resultingproduct is vacuum distilled ten minutes at 2 mm. Hg. Constants on theproduct are as follows: acid value, 7; viscosity, N-O at 66.7 percentsolids in styrene; color, 12 at 66.7 percent solids in styrene.

Styrene (120 grams) containing 500 p.p.m. tertiary butyl catechol, theproduct of this example (180 grams), and'catalyst (six grams) areblended together and a casting is prepared from this solution using theprocedure of Example 1. The following strength properties are obtainedfrom this casting:

Tensile strength p.s.i 5800 Flexure strength p.s.i 11000 Impact strengthft. lb./inch of notch 0.25

Alpha-hardness 103 Example 4 In order to prepare a branched chainthermoplastic polyester having six branch chains and a theoreticalmolecular weight of 2606, using dipentaerythritol as the initiator,propylene oxide, dipentaerythritol, maleic anhydride, and phthalicanhydride are employed in a mol ratio of 11 to /3 to 4 to 4. Thedipentaerythritol (61.2 grams), maleic acid anhydride (275.5 grams),phthalic acid anhydride (415.9 grams) and propylene oxide (448.4 grams)are reacted together following the procedure set forth in Example 1. Theaddition of propylene oxide to the flask contents requires approximately15 hours after which the temperature is raised to 150 C. as the refluxpermits. Temperature is held at 150 C. until reflux ceases and theproduct is then vacuum distilled for ten minutes at 2 mm. Hg. A producthaving the following constants results: acid value, 3; viscosity, W-X at66.7 percent solids in styrene; color, 4-5 at 66.7 percent solids instyrene.

Styrene (120 grams) containing 500 ppm. tertiary butyl catechol, theproduct of this example (180 grams) and catalyst (six grams) are blendedtogether and made into a casting using the procedure described inExample 1. The blend produces a clear, rigid casting which possesses thefollowing strength properties:

Tensile strength p.s.i- 6600 Flexure strength p.s.i 15000 Impactstrength ft. lb./inch of notch 0.26

Alpha-hardness 1 12 Example 5 Part (a).-A polyhydroxy polyether isprepared by reacting bisphenol, epichlorohydrin, ethylene chlorohydrin,and sodium hydroxide in the following molar ratios:

Mols Bisphenol 5 Epichlorohydrin 4 Ethylene chlorohydrin 2 Sodiumhydroxide 6.9

12 a Gardner-Holdt viscosity of RS at forty percent solids in butylcarbitol. The resulting linear polyether polymer contains two terminalalcoholic hydroxyl groups and four intermediate alcoholic hydroxylgroups and has a molecular weight of approximately 1400.

Part (b).-To prepare a branched chain thermoplastic polyester having sixbranch chains, using the polyhydroxy polyether of Part (a) as theinitiator, propylene oxide, polyhydroxy polyether, maleicanhydride andphthalic anhydride are employed in 21 mol ratio of 11 to /3 to 4 to 4.The polyhydroxy polyether (272.4 grams), maleic acid anhydride (224.4grams), phthalic acid anhydride (338.4 grams), and propylene oxide(340.0 grams) are reacted together according to the procedure. set forthin Example 1. The propylene oxide addition requires ap proximately 15hours. The temperature is then raised to 150 C. and held at thistemperature until reflux ceases. The product, after being vacuumdistilled for ten minutes at 2 mm. Hg has the following constants: acidvalue, 1.9; viscosity, X-Y at 66.7 percent solids in styrene; color, 3-4at 66.7 percent solids in styrene.

Styrene grams) contalning 500 p.p.m. tertiary butyl catechol, theproduct of this example (180 grams), and catalyst (six grams) areblendedtogether and processed into a casting using the proceduredescribed in Example 1. The resulting casting is clear and rigid andpossesses the following strength properties:

Tensile strength p.s.i 5700 Flexure strength p.s.i 9000 Impact strengthft. lb./inch of notch 0.27 Alpha-hardness Example 6 Using pyromelliticacid as the initiator, to prepare a polyester having four branch chains,propylene oxide, pyromellitic acid, maleic anhydride and phthalicanhydride are used in a mol ratio of 11 to /2 to 4 to 4. The

pyromellitic acid (87.1 grams), maleic acid anhydride (268.9 grams),phthalic acid anhydride (406.1 grams) and propylene oxide (437.6 grams)are reacted together in accordance with Example 1. The addition of thepropylene oxide requires approximately four hours. The temperature isthen raised to C. as reflux permits and held until reflux ceases.Volatiles are then distilled 05 under a vacuum of 2 mm. Hg for tenminutes after which the following constants are determined: acid value,31; viscosity, Y-Z at 66.7 percent solids in styrene; color, 8-9 at 66.7percent solids in styrene.

Styrene (120 grams) containing '500 ppm. tertiary butyl catechol, theproduct of this example grams), and catalyst (six grams) are blendedtogether and made into a /8" casting, using the procedure described inExample 1. The product is a clear, rigid casting, having the followingstrength properties:

Tensile strength p.s.i 7700 Flexure strength p.s.i 15000 Impact strengthft. lb./inch of notch 0.29

Alpha-hardness 1 15 Example 7 (247.2 grams) are weighed into a twoliter, three neck,

round bottom flask, provided with a stirrer, thermometer,

dropping funnel and six bulb water condenser, the latter,

attached directly to oneneck of the flask. The flask contents arestirred continuously and heated to 150 C. At this temperature, butylglycidyl ether (506.4 grams) is added through the dropping funnel over aperiod of 13 approximately two hours. After this addition the flaskcontents are heldat 150 C. After two hours, the acid value is found tobe 21.2 and after five hours it is 18.5. The product is found to havethe following constants: acid value, 18.4; viscosity, X-Y at 66.7percent solids in styrene; color, 813 at 66.7 percent solids in styrene.

Example 8 With phloroglucinol as the initiator, a branched chainthermoplastic polyester having three branch'chains is prepared byreacting phloroglucinol (44.0 grams), maleic acid anhydride (1065grams), phthalic'acidanhydride (160.5 grams) and propylene oxide (1890grams) following the procedure for Example 2. The mol ratio ofmonoepoxide (propylene oxide) to phloroglucinol to maleic anhydride tophthalic anhydride is 12 to 1 to 4 m4. The addition of the propyleneoxide to the flask contents requires approximately eight hours. Thetemperature of the flask contents is raised to 150 C. as reflux permitsand held at this temperature until reflux ceases. A product resultshaving the following constants: acid value, 30; viscosity, T-U at 66.7percent solids in styrene; color, 18+ at 66.7 percent solids in styrene.

Example 9 To prepare a branched chain thermoplastic polyester havingthree branch chains, using raw castor oil as the initiator, propyleneoxide, raw castor oil, maleic anhydride and phthalic anhydride areemployed in a mol ratio of 9 to /3 to 5 to 5. The raw castor oil (166.0grams), having a weight per alcoholic hydroxyl of 332, maleic acidanhydride (245.3 grams), phthalic acid anhydride (370.3 grams) andpropylene oxide (300.0 grams) are reacted together as set forth inExample 1. The addition of the propylene oxide requires approximately 11hours, after which the temperature is raised to 150 C. and held untilreflux ceases. After vacuum distillation (ten minutes at 2 mm. Hg) theproduct is found to have the following properties: acid value, 73;viscosity, WV at 66.7 percent solids in styrene; color, 9-10 at 66.7percent solids in styrene.

Styrene (120 grams) containing 500 ppm. tertiary butyl catechol, theproduct of Example 6 (180 grams), and catalyst (six grams) are blendedtogether and processed into a casting using the procedure described inExample 1. The product is a clear, semi-rigid casting having thefollowing strength properties:

Tensile strength p.s.i 7200 Flexure strength p.s.i 11900 Impact strengthft. lb./inch of notch 0.31

Example 10 Part (a).-A 65-35 vinyl toluene-hydroxy propyl acrylatecopolymer is prepared by combining (in the presence of 67 parts of a5050 mixture of xylene and methyl isobutyl ketone, in a flask equippedwith condenser, thermometer and agitator) 65 parts of vinyl toluene,15.5 parts of propylene oxide and 19.5 parts of acrylic acid (partsbeing based on a total of 100 parts for the three reactants). Catalystsfor the process, 1.0 part of benzoyl peroxide and 2.0 parts of a 35percent solution of benzyl trimethyl ammonium hydroxide in methanol, areadded; The reaction mixture is refluxed until an acid value of less thanone is obtained, approximately 14 hours. The resulting 54.7 percentsolids solution contains ahydroxyl-containing linear copolymer having aweight per hydroxyl'group of 371. Since the average molecular weight ofthe copolymer is believed to be in the neighborhood of 20,000, eachmolecule contains an average of 50' to 60 hydroxyl groups.

Part (b).-To use the vinyl toluene-hydroxy propyl acrylate copolymer ofPart (a) of this example as the initiator, a branched chainthermoplastic polyester, having from about 50 to 60 branch chains isprepared from a ratio of. mols of monoepoxide (propylene oxide) toequivalents of copolymer to mols of phthalic anhydride of 5 to 1 to 5,the copolymer (145.5 grams of a 54.7 percent solids solution), phthalicacid anhydride (158.4 grams), xylene (134.0 grams), and propylene-oxide(62.1 grams) are reacted in accordance with the procedure of Example 7,except that the reflux temperature is from to C. The addition of thepropylene oxide requires approximately three hours. The flask contentsare held at a moderate reflux for an additional six hours, at which timethe temperature has reached 138 C. The product is cooled and combinedwith50 grams of methyl isobutyl ketone. The acid value of the solidsportion of the product is 9.4.

Example 11 A branched chain thermoplastic polyester having from about 50to 60 branch chains is prepared using the vinyl toluene-hydroxy propylacrylate copolymer of Example 10, Part (a) as the initiator. The ratioof mols of monoepoxide (propylene oxide): to equivalents of copolymer tomolsof phthalic anhydride is 10 to 1 to 10. The theoretical molecularweight of each branch is 2062. The copolymer (83.2 grams of a 54.7percent solids solution), phthalic acid anhydride (182.7 grams), xylene(162.4 grams), and propylene oxide (71.7 grams) are reacted inaccordance with the procedure of Example 10. The propylene oxide isadded to the flask contents over a period of approximately six hours, ata rate suflicient to maintain a moderate reflux at 120 C. to 125 C.Flask contents are held at moderate reflux for four hours after all thepropylene oxide is added. A mixture of 150 grams of methyl isobutylketone and 20 grams of Cellosolve acetate is added to the product. Theacid value of the solids portion of the product is 10.8.

Example 12 A branched chain thermoplastic polyester having from about 50to 60 branch chains is prepared using the vinyl toluene-hydroxy propylacrylate copolymer of Example 10, Part (a) as the initiator. The ratioof mols of monoepoxide (propylene oxide) to equivalents of copolymer tomols of phthalic anhydride is 20to 1 to 20. The theoretical molecularweight of each branch is 4124. The copolymer (45.3 grams of a 54.7percent solids solution), phthalic acid anhydride (19.7 grams), xylene(89.7 grams), methyliisobutyl ketone (89.6 grams), and propylene oxide(78.0 grams) are reacted in accordance with the procedure of Example 10.A portion of the propylene oxide (50 grams) is added to the flaskcontents at 120 C. to 125 C. over a period of 4% hours. After thisportion of propylene oxide is added to the flask contents, they are heldapproximately four hours at a moderate reflux of 120 C. to C. Benzyltrimethyl ammonium chloride crystals (three grams) are then added to theflask contents to catalyze the reaction. The additional 28 grams ofpropylene oxide are then added at 120 C. to 130 C. over a period ofapproximately 40 minutes. The flask contents are then held. at amoderate'reflux for an additional 40 minutes. The product is thencombined with Cellosolve acetate 50 grams). The acid value of the solidsportion of the product is 15.7.

Example 13' To prepare a carboxyl terminated-branched chainthermoplastic polyester having from about 50 to 60'branch chains, the.vinyltoluenehydroxy propyl? acrylate copolymer of Example 10 is used asan initiator. The ratio of mols of monoepoxide (propylene oxide) toequivalents of copolymer to mols of'phthalic anhydride is 4 to 1 to 5.The initiator (221.0 grams of a 54.7 percent solids solution of thecopolymer) and phthalic acid. anhydride (212.8 grams) are Weighed into aone liter flask equipped with stirrer, thermometer, dropping funnel andsix bulbwater condenser. The flask contents are heated to'a temperatureof 120 C. to 125 C. while being constantly stirred. Propylene oxide(66.4 grams) is added to the flask contents through the dropping funnelover a period of approximately two hours. At this point, xylene (50grams) is then added and the temperature is raised to reflux condititons(127 C. to 130 C.). The system is held at moderate reflux for another 80minutes, at which time the reflux temperature is 138 C. to 140 C.Additional 50 grams of xylene and 50 grams of methyl isobutyl ketone areadded and the product is allowed to cool. The following constants aredetermined on the product: Non-volatiles (two hours at 150 C.), 57.9percent; acid value (nonvolatile portion), 54.3 viscosity of the cooledproduct, Va styrene, Q-R.

Example 14.Vinyl toluene/butyl acrylate/methacrylic acid copolymer with20.4 percent phthalic anhydride modification To a suitable reactionflask equipped with a mechanical stirrer, condenser, thermometer, anddropping funnel were added 59.5 parts of xylene and 59.5 parts of methylisobutyl ketone. To the dropping funnel were added 44.7 parts of vinyltoluene, 98.1 parts of butyl acrylate, 35.7 parts of methacrylic acidand 3.6 parts of benzoyl perox ide. Heat was applied to the flask and at120 C. addition of the monomer-catalyst solution was begun, the additionbeing completed in 45 minutes. Heating was continued at 118-120 C. forone hour and 50 minutes. Sixty parts of xylene were then added to theflask and heating was continued at 118 C. for 45 minutes. After thefurther addition of 100 parts of xylene, the reactants were heated at118-119 C. for four hours and minutes. The resulting copolymer solutionhad a solids content of 36.8 percent indicating 94.5 percent conversionof monomers to polymers.

The copolymer solution was cooled to 67 C. and three parts oftriethylamine were added. Heat was applied and at 110 C. the addition of26.5 parts of propyleneoxide was begun and completed over a period of 33minutes. Heating was continued at 103120 C. for three hours and 18minutes, after which time the acid value, on solids basis, was 7. Thereactants were cooled to room temperature and 61.2 parts of phthalicanhydride were added. Heat was reapplied and at 110 C. the addition of33.8 parts of propylene oxide was begun and completed over a period of42 minutes. The reactants were then heated at 113120 C. for 35 minutes.The resulting phthalic modified copolymer solution had an acid value of4 on solids basis and a Gardner-Holdt viscosity of R at 48.6, percentsolids.

To 15.4 parts of the modified copolymer solution were added five partsof an isobutylated methylol melamine resin at 50 percent solids inisobutynol. Three mil films were prepared on glass and were baked 30minutes at 150 C. The resulting well-cured films were clear andcolorless, had good mar resistance, and were flexible and tough.

Example 15 .--Butyl acrylate/methacrylic acid copolymer modified with20.4 percent phthalic anhydride To a suitable reaction flask equipped asdescribed in Example 14 were added 59.5 parts of xylene and 59.5 partsof ethylene glycol monoethyl ether acetate. To the dropping funnel wereadded 142.8 parts of butyl acrylate, 35.7 parts of methacrylic acid and3.6 parts of benzoyl peroxide. Heat was applied raising the temperatureof the flask contents to 120 C. The addition of the monomercatalystsolution was begun and continued over a period of 45 minutes whileholding the temperature between 117- 135 C. The temperature was held at117-126 C. for six hours. The solids content of the copolymer solutionwas 59.9 percent indicating 100 percent conversion of monomers topolymers.

To the copolymer solution were added 160 parts of xylene and three partsof triethyl amine. Heat was applied and at 110 C., 26.5 parts ofpropylene oxide were slowly added over a period of 41 minutes. Thereactants were then held at 118120 C. for two hours and minutes, afterwhich time the acid value was 5.4, on solids basis.

16 The reactants were cooled to C. and 61.2 parts of phthalic anhydridewere added. Heatwas reapplied and at C., 33.8 parts of propylene oxide.were added over a period of 52 minutes. After heating at 110 C. for onehour and 17 minutes, the acid value of the reactants on i a solids basiswas less than one. The resulting phthalic modified copolymer solutionhad a Gardner-Holdt viscosity of F-G.

A blend was prepared'from 14.4 parts of the modified copolymer solution,five parts of an isobutylated methylol melamine resin at 50 percentsolidsin isobutanol, 0.6 part xylene, and 0.16 part of the morpholinesalt of butyl acid phosphate at 50 percent solids in the monobutyl etherof ethylene glycol. Three mil films were prepared on and were baked at150 C. for 30 minutes. The wellcured films were clear and exhibited highgloss, excellent mar resistance and excellent flexibility.

Example l6.-Butyl acrylate/methacrylic acid copolymer with 20.9 percentphthalic anhydride modification Using the same procedure as described inExamples 14 in isobutanol, 2.3 parts of ethylene glycol monomethyl etheracetate and five parts of n-butanol. Three mil films were prepared onglass and were baked at 150 C. for 30 minutes. The well-cured films hadgood mar resistance and adhesion.

Example 17.Butyl acrylate/methacrylic acid copolymer with 21.2 percentphthalic anhydride modification Using the same procedure as previouslydescribed, a copolymer solution was prepared from 150 parts of butylacrylate and 36.9 parts of methacrylic acid with 3.6 parts of benzoylperoxide catalyst, 59.5 parts of xylene and 59.9 parts of ethyleneglycol monomethyl ether acetate. The resulting copolymer solution wasfurther reacted as previously described with 63.6 parts of phthalicanhydride and 49.8 parts of propylene oxide using three parts oftriethyl amine catalyst to an acid value of 23.1 on

solids basis.

12.5 parts of the resulting solution (60 percent solids) was blendedwith five parts of an isobutylated methylol melamine resin at 50 percentsolids in isobutanol, and 2.5 parts of xylene. Three mil films wereprepared on glass and were well cured after 30 minutes heating at 150 C.The films had excellent mar. resistance and good adhesion. Two mil filmsprepared on electrolytic tin plate and baked for 30 minutes at 150 C.passed a 28 inch-pound impact test.

Example 18.-Butyl acrylate/styrene/methacrylic acid copolymer modifiedwith 40 percent phthalic anhydride A copolymer solution was prepared byreacting 65.7 parts ot-butyl acrylate, 28.2 parts of styrene and 23.4parts of methacrylic xylene, and "15.6 parts of ethylene glycolmonoethyl ether acetate. After the addition of 100 parts of xylene, thecopolymer solution was heated to C. 1.5 parts of benzyl dimethyl. aminewere added and addition of 15.2 parts of propylene oxide wasbegun. Afterthe addition of the. propylene oxide wascompleted .(37 minutes), thetemperature was held at 105 C. to 121 C. for one hour and 40 minutes, atwhich time the acid value was 24.9 on solids basis. The reactants werecooled to 30 C. and parts of phthalic anhydride were added. Heat wasreapplied and at 1120C., the addition of 475 parts of propylene oxidewas glass phthalic anhydride with three begun. The propylene oxide 1 wasadded over a period of one hour and 12 minutes, during whichtime thereaction temperature dropped to 98 C. Heating was continued for one hourand 45 minutes while the temperature slowly rose to 121 C. The acidvalue was then 26.5 on solids basis. Fifty parts of ethylene glycolmonoethyl ether acetate were addedand the reactants were heated at 120C. to 123 C. for 30 minutes, after which time the acidvalue was 23.7.After the addition of 50 parts of ethylene glycol monoethyl etheracetate, the resulting solution had a Gardner-Holdt viscosity of- V, aGardner color of 3 to 4 and a solids content of 51.4 percent.

A blend was prepared from 85 weight percent of the modified copolyrnerand percent of an isobutylated methylol melamine resin (based onsolids). Three mil filmswere prepared on glass and were baked at 150 C.for minutes. The resulting clear, we1l-cured films had excellent marresistance and good water resistance.

Example 19.Butyl acrylate/styrene/methacrylic acid copolyrner with 21.2percent phthalic anhydride modification To a suitable reaction flaskequipped as described in Example 14 were added 95.2 parts of xylene,23.8 parts of ethylene glycol monoethyl ether acetate and 9.3 parts ofcumene hydroperoxide. Heat was applied raising the temperature of theflask contents to 135 C. A monomer mixture parts 'butyl acrylate, 15parts styrene and 12.3

parts :methacrylic acid) was added over a period of 45 minutes whileholding the temperature at 135 C. to 140 C. The temperature was thenheld at 135 C. to 138 C.

for six hours. Solids content of the solution was then determined to be95.1 percent indicating 97 percent conversion of monomers to polymers.

Xylene, 81 parts, and benzyl dimethyl amine, 1.5 parts, were added tothe copolyrner solution and a slow stream of nitrogen was introducedinto the flask. 26.5 parts of propylene oxide were added to the flaskover a period of 35 minutes while holding the temperature at 100 C. to115 C. After additional heating at 110 C. to 120 C., for two hours and40 minutes, the acid value, based on theoretical solids, was 23.9. Theflask contents were cooled to C. and 63.6 parts of phthalic anhydridewere added. Heat was reapplied raising the temperature to 115 C. 23.3parts of propylene oxide were then added over a period of 45 minutes at115 C. After 70 minutes additional heating at 120 C., the resultingphthalic modified copolyrner solution had a Gardner-'Ho-ldt viscosity ofZ to Z Gardner color of 1, solids content of 58.2 percent and acid valueof 28.8 based on solids.

Blends were prepared from the modified copolyrner and a butylatedrnethylol melamine resin (8570 percent copolyrner solids to 15-30percent melamine resin solids). Well cured films having good marresistance, hot water resistance and adhesion were obtained after 30minutes at 150 C.

Example 20. Butyl acrylate/styrene/methacrylic acid copolyrner with 32.9percent phthalic anhydride modification A copolyrner was prepared asdescribed in Example 19 from 34.5 parts of styrene, 80.4 parts of butylacrylate and 28.5 parts of methacrylic acid using 7.2 parts of cumenehydroperoxide catalyst and 76.5 parts of xylene and 19.1 parts ofethylene glycol monoethyl ether acetate as solvents. The resultingcopolyrner solution had a solids content of 60 percent indicating 100percent conversion of monomers to polymers.

To the copolymer solution were added 100 parts of xylene and 1.5 partsof benzyl dimethyl amine. 19.3 parts of propylene oxide were added overa period of 23 minutes at 100 C. to 115 C. The reactants were thenheated for two hours at 120 C. under a slow stream of nitrogen. The acidvalue at this point was 30.1, based on solids. After an additional onehour at 120 C., the acid value was 19.6, based on solids. The flaskcontents were cooled to 30 C. and 98.7 parts of phthalic anhydride wereadded. Heat was reapplied and at 115 C., 38.6 parts of propylene oxidewere added over a one hour period. After two hours and 30 minutesadditional heating at 120 C., the acid value was 21.1 based on solids.The resulting phthalic modified copolyrner solution had a Gardner- Holdtviscosity of Z; to Z and a Gardner color of 3-4 at 59.6 percent solids.

Blends were prepared from the modified copolyrner and an isobutylatedrnethylol melamine resin using -percent to 70 percent copolyrner and 15percent to 30 percent melamine resin (based on solids). Well cured filmshaving good mar resistance, adhesion and hot water resistance wereobtained after a 30 minute bake at 150 C.

Example 21.-Butyl acrylate/styrene/methacrylic acid copolymer modifiedwith 15.2 percent maleic anhydride As described in Example 19, acopolymer was prepared from 112.2 parts of butyl acrylate, 48.6 parts ofstyrene and 39.6 parts of methacrylic acid using 10 parts of cumenehydroperoxide catalyst and as solvents 76.5 parts of xylene and 19.1parts of ethylene glycol monoethyl ether acetate.

To the copolymer solution were added 1.2 parts of benzyl dimethyl amineand parts of xylene. Thirtyfive parts of propylene oxide were added tothe solution over a period of two hours at C. to 113 C. Heating wascontinued for three hours at 107 C. to 118 C. after which time the acidvalue of the reactants on solids basis was 7.7. Five additional parts ofpropylene oxide were added to the flask and heating at 120 C. wascontinued for one hour and 30 minutes to an acid value of 2.1. Thereactants were cooled to 75 C. and 45.6 parts of maleic anhydride wereadded. The temperature was raised to 110 C. and 14 parts of propyleneoxide were added in 31 minutes. Heating was continued at 117 C. to 121C. for 50 minutes. The acid value at this point was 39.2 on solidsbasis. 104.4 parts of xylene were added and heating at 120 C. wascontinued for 30 minutes. After the addition of 100 parts of xylene, theacid value was determined to be 27.8 on solids basis.

Three mil films were prepared on glass from a blend of the modifiedcopolymer solution and an isobutylated methylol melamine resin (85-weight percent copolyrner and 15 weight percent melamine resin based onsolids). After a 30 minute bake at 150 C., the films were well cured andhad excellent gloss, mar resistance, adhesion and flexibility.

Example 22.Maleinized oil as initiator for polyester To a suitablereaction flask equipped with a thermometer, stirrer, condenser anddropping funnel were added 167.4 parts of linseed oil and 56.1 parts ofmaleic anhydride. The reactants were heated at 200 C. for two hours and30 minutes to form the maleic adduct of the oil. The adduct was cooledto 100 C., 15.5 parts of water and three parts of triethyl amine wereadded, and heating at 100 C. was continued for two hours to open theanhydride rings. Seventy-three parts of propylene oxide were added overa one hour and 30 minute period while holding the temperature at 76 C.to 85 C. Heating was continued for nine hours and 20 minutes while thetemperature rose to- C. and the acid value leveled ofl at 38.6. Onehundred parts of xylene were added and were distilled off to remove anywater in the flask. 140.7 parts of phthalic anhydride were added and thereactants were heated at 120 C. for one hour. Seventy-three parts ofpropylene oxide were then added over a one hour period at 98 C. to 110C. After one hour and 40 minutes heating, the temperature rose to 120C., and the acid value was 12.8. The product when dissolved at 68.5percent solids in xylene had a Gardner-Holdt viscosity of Z To 14.6parts of the solution of polyester modified maleinized oil were blended8.7 parts of xylene and 16.7 parts of a butylated urea-formaldehyderesin at 60 percent solids in xylene and butanol. Three mil films wereprepared on glass and were baked for 30 minutes at 180 C. Well-curedfilms having excellent flexibility, mar resistance and adhesion wereobtained.

Example 23.Novolak resin as initiator for polyester To a reaction flaskequipped as described in Example 14 were added 66.6 parts of apara-phenyl phenol formaldehyde resin having a melting point of 90 C. to107 C., 82.2 parts of phthalic anhydride, 54.6 parts of maleic anhydrideand 20 parts of xylene. Heat was applied to the flask raising thetemperature of the reactants to 120 C. One part of pyridine catalyst wasadded and slow addition of 96.6 parts of propylene oxide was begun whileholding the temperature between 115 C. and 125 C. All the propyleneoxide was added after two hours and 15 minutes. The viscosity of thereactants was reduced with 100 parts of xylene and the flask contentswere heated for six hours at 90 C. to 100 C. to complete the polyesterformation. The resulting product had an acid value of 28.5 on a solidsbasis and a percent solids of 71.5.

Films prepared from this solution and 30 to 50 weight percent on solidsbasis of an alkylated urea-formaldehyde resin were well cured after 30minutes at 180 C.

Example 24.Epoxy resin-phthalic alkyd containing 21 percent phthalicanhydride To a suitable reaction flask were added 319.2 parts of aglycidyl polyether of bisphenol A (reaction product of 1.57 mols ofepichlorohydrin and one mol of bisphenol A having an epoxide equivalentweight of 485), 280.8 parts of soya fatty acids and parts of xylene. Thereactants were heated to 200 C. and were held at 200 C. for seven hoursuntil the acid value was 7.5.

To 218 parts of the above epoxy ester (93 percent solids in xylene) wereadded 69.3 parts of phthalic anhydride and 50 parts of xylene. Thetemperature was raised to 100 C. and 1.5 parts of tertiary aminecatalyst were added. Addition of 52.3 parts of propylene oxide was begunand was continued for three hours while holding the temperature between97 C. and 100 C. After an additional two hours heating at 101 C. theacid value was 2.5. When dissolved at 74 percent solids in xylene, theGardner-Holdt viscosity was W to X.

Films were prepared from the above reaction product using 0.03 percentcobalt and 0.03 percent manganese driers. After drying overnight thefilms were tack free and hard.

Example 25.Epoxy resin-phthalic alkyd containing 31 percent phthalicanhydride Using the same procedure as described in Example 24, 321 partsof the glycidyl polyether described in Example 24 and 179 parts of soyafatty acids were reacted to an acid value less than one. Three hundredand fifty-eight parts of the epoxy ester solution (75 percent solids inxylene) were then reacted with 152.5 parts of phthalic anhydride and80.5 parts of propylene oxide to an acid value of 1.4. Films preparedfrom resulting product, using 0.03 percent cobalt and 0.03 percentmanganese driers, were well cured after an overnight dry.

Example 26.-Epoxy resin-phthalic alkyd containing 23 percent phthalicanhydride As described in Example 24, 225.2 parts of a glycidylpolyether of bisphenol A (reaction product of 1.22 mols epichlorohydrinand one mol of bisphenol A, having an epoxide equivalent weight of 900)were reacted with 174.8 parts of soya fatty acids to an acid value lessthan one. Two hundred and eighty-eight parts of a solution of the epoxyester in xylene (65.7 percent solids) were reacted with 69.9 parts ofphthalic anhydride and 41.4 parts of propylene oxide to an acid value of1.3. Films prepared from this resin, using 0.03 percent cobalt and 0.03percent manganese driers, were well cured after an overnight dry.

Example 27.D.ifatty ester of the diglycidyl ether of bisphenol A asinitiator for polyesters were added over a period of six hours and 45minutes while holding the temperature between 114 C. and.134. C. Theresulting product had an acid value of 15.

185.3 parts of the reaction product were dissolved 111 116 parts ofstyrene with six parts of benzoyl peroxide 7 catalyst. The solution waspoured into a mold and was cured by heating at C. for one hour and at121 C. for one hour. The cured casting had a tensile strength of 1800p.s.i. and a flexure strength of 2200 p.s.i.

Example 28.-Rosin-maleic adduct as initiator for polyester To a suitablereaction flask equipped with a stirrer, con-- denser, and thermometerwere added 436 parts ofmaleic anhydride and 1564 parts of rosin(softening point 78 0., acid value 166). Heat was applied raising thetemperature to 160 C. in 36 minutes. The temperature was then 1 thereactants to ambient temperatures, 254.4 parts of maleic anhydride and192 parts of phthalic anhydride were added. Heat was reapplied and at120C. addition of propylene oxide was begun. Three hundred andsixtythree parts of propylene oxide were added over a period of 16 hourswhile keeping the temperature between 120 C. and 140 C. The resultingproduct had an acid value of 34.6.

One hundred and eighty parts of the above reaction product weredissolved in 120 parts of styrene with six parts of benzoyl peroxidecatalyst. The reactants were poured into a mold and were cured after onehour at 75 C. and one hour at 121 C.

Example 29 To a suitable reaction flask equipped with a mechanicalstirrer, thermometer, condenser and dropping funnel were added 22.8parts of trimethylol maleic anhydride and 228 parts of phthalicanhydride. Heat was applied raising the temperature of the reactants to75 C. Twenty parts of toluene were added andthe temperature of thereactants was raised to 125 C. where a clear solution was obtained.198.6 parts of propylene oxide were added to the dropping funnel andslow addition of propylene oxide to the flask was begun. The propyleneoxide was slowly added over a period of nine hours and 30 minutes whilekeeping the temperature between C. and 125 C. Heating was continued at120 C.

to 123 C. for six hours and 30minutes. At the end of i this heatingperiod,,the acid value of the reactants was 90. Ten parts of toluenewere added to the flask and an additional 30 parts of propylene oxidewere added over a period of three hours and 45 minutes, while keepingthe temperature at C. to C. After heating for three more hours, the acidvalue was 46. The volatiles were removed from the reaction product byheating the a suitable reaction flask were added 59.4 parts of 1 thediglycidyl ether of bisphenol A (epoxide equivalent,

C. in order to i open the anhydride rings with the glycol. After coolingpropane, 150.6 parts of Example 30' Seven hundred and thirty-two gramsof. vinyl toluene, 405 grams acrylic acid, 363 grams propylene oxide, 30grams benzoyl peroxide, 42.8 grams benzyl trimethyl ammonium hydroxide(35 percent solution in methyl alcohol), 850 grams xylene and 150 gramsmethyl isobutyl ketone were charged into a five' liter flask equippedwith an agitator, thermometer, and a six bulb condenser attacheddirectlyto the flask. The contents of the flask were heated to refluxtemperature (75-80 C.) with agitation and heldat maximum reflux for fivehours. One hundred and ninety-five grams of'xylene, 35 grams methylisobutyl ketone were then added and reflux continued until the reactionsolution had an acid value of 1 to 2 and a viscosity U-V. The contentsof the flask are then distilled'to remove the excess propylene oxideat'a temperature of 120-123" C. Five hundred and ninety-one grams ofphthalic anhydride were then added to the reaction mixture in the flasktogether with 213 grams of xylene and 598 grams methyl isobutyl ketone'.The reaction mixture was then held at 100 C. for approximately one hour.

The resulting product had a solids content of 46.6 percent, a viscosityof Z Z and a weight per carboxylic acid group (solids) of 422.

The foregoing examples illustrate the preparation of highly branchedchain thermoplastic or linear polyesters according to this invention.The formation of the branched chain polyesters is initiatedby thepresence of small amounts of polyfunctional compounds containing activehydrogens which function as reaction centers or nuclei from which thebranched chains emanate, the number of chains, as indicated, being equalto the functionality of the nucleus-forming compound. The precedingexamples show the drop-wise addition of monoepoxide to the flaskcontents. It is understood, however, that other methods of preparing thepolyesters of this invention can be used. Thus, while it is convenientto slowly add the monoepoxide, the three reactants can all be initiallycombined. In the case of an alcoholic hydroxyl initiator since the rateof reaction between this initiator and the monoepoxide is negligiblecompared to the reaction of alcoholic hydroxyls with anhydride, thereactions will proceed in the same order as those in the illustrativeexamples. In the case of a carboxyl or phenolic hydroxyl initiator theepoxide reacts first with the initiator to produce alcoholic hydroxylswhich react with anhydride groups.

A feature of this invention is that it is theoretically possible toprepare hydroxyl, carboxyl, or hydroxylcarboxyl terminated polyesters.Example 13 is illustrative of how, by using proper ratios of initiatorto anhydride to monoepoxide a highly branched, high molecular weightpolyester, whose branches terminate with carboxyl groups, can beprepared.

Another feature of the invention is that the saturated and unsaturatedpolyesters can be cured with aldehydeamine or aldehyde-amide condensatessuch as ureaformaldehyde or melamine-aldehyde condensates (e.g., afusible alkylated condensate of an aldehyde with urea or melamine) togive excellent film-forming compositions. In general, the branchedpolyester of this invention is reacted with about 30 to 70 percent byweight of aldehyde condensate, preferably with from 40 to 60 percent.This can best be illustrated by the following examples. Theurea-formaldehyde resin used in the examples is a butyl- 22ated-ureaeformaldehyde resin having a non-volatile content-of'sixtypercentin asolvent mixture of 87.5 percent butyl alcohol, and-12.5percent xylene and a viscosity of U-X;

Example Y 10.0 grams of polyester of Example 2 167 grams ofabovebutylatedurea-formaldehyde resin at sixty percent solids 10.3 grams oftoluene 3.0 grams of Cellosolve' acetate The .abovematerials are blendedtogether by dissolving the polyester in the. two solvents by theaid ofheat and Example Z 10.0 grams of polyester of Example 3' 16.7 grams ofabove butylated urea-formaldehyde resin at sixty percent solids 10.3grams of toluene 3.0 grams of Cellosolve acetate The-above :materialsare'blended together by dissolving the polyester in the twosolvents'with the air. of heat. The butylated urea-formaldehyde resin; is. thenadded. This solution contains polyester and urea-formaldehyde resinsolids in a 5050 ratio. A three mil film of the above blend is depositedon a glass panel and baked 30 minutes at C. The resulting film hasoutstanding gloss, hardness, flexibility, mar-resistance, toughness, andadhesion properties.

As indicated hereinbefore, a feature f0 this invention is thatpolyesterscan bepreparedhaving a multiplicity of unsaturated branchchains. For example, when an unsaturated anhydride is employed, forexample, mixtures of maleic acid anhydride and phthalic acid anhydride,polyester branches joined to the initiator will contain recurring doublebonds. This class of unsaturated polyesters is of particular importancebecause the polyesters can be cured with compounds such as styrene,yielding excellent compositions. A further feature is that following theteachings of this invention more highly branched chain polyesters areprepared than known heretofore. Methods for preparing polyesters havinga large number of branch chains are not readily available. Particularlymethods are not available whereby polyesters can be prepared having apredetermined number of branch chains and approximately predeterminedmolecular weights.

Because of the valuable properties possessed by esters prepared inaccordance with this invention and because they can be varied widely inphysical properties, the polyesters described herein are suitable fordecorative, industrial and maintenance finishes, adhesives, cable andwire coatings, laminates, molded plastic articles and the like.Plasticizers, pigments, dyes, reinforcing agents, and similar materialscommonly used in formulating polymeric compositions can be used with thepolyesters of this invention. Since such variations will occur to thoseskilled in the art, it is obvious that these embodiments are within thescope of this invention.

We claim:

1. In the preparation of thermoplastic polyesters from dicarboxylic acidanhydrides and monoepoxides, the process for preparing branch chainpolyesters having end groups which do not react with each other duringpreparation, comprising a compound which acts as a reaction initiatorwhich is a monomer, a polymer or a copolymer having at least threefunctional constituents of the group consisting of carboxyl radicals,phenolic radicals or com- 'binations thereof, the number of such groupsbeing equal to the number of branch chains desired, reacting theinitiator, the anhydride and the monoepoxide by heating the reactants atan elevated temperature below 150 C. sufficient to bring about areaction of the anhydride with the alcoholic hydroxyl group formingcarboxyl groups, the reaction of monoe'poxide with the phenolic hydroxylgroups to form alcoholic hydroxyl groups, as well as a reaction ofmonoepoxide with the carboxyl groups also forming alcoholic hydroxylgroups and maintaining the temperature below that at whichacarboxy-hydroxy reaction takes place so that end groups of polyesterchains growing by the successive addition of anhydride and rnonoepoxideto the and form water, said monoepoxide being free of substituentscapable of reacting \m'th an acid anhydride.

2. The process of claim 1 wherein the initiator is pyromellitic acid.

3.'The process of claim phloroglucinol.

4. The process of claim 1 wherein the initiator is a bis phenolterminated bisphenol-epichlorohydrin condensate made by reacting n molsof epichlorohydrin with n+1 mols of bisphenol in the presence of n molsof sodium hydroxide.

5. -A monomer, polymer or copolymer containing at least three carboxylor pheno c hydroxyl groups, or combinations thereof, in which at leastthree of the terminal hydrogen atoms of said groups are replaced by aradical having the following structural formulae:

1 wherein the initiator is initiator, do not react with each other.

or combinations thereof, where (a) where R =H, an alkyl radical, analkenyl radical,

or CH O-R where R =an alkyl, alkenyl or aryl radical,

(b) Y=nucleus of a dibasic acid anhydride and (c) x=at least 1.

6. The product of claim 5 wherein the moiety having thedthree functionalgroups is a nucleus of pyromellitic aci 7. The product of claim 5wherein the moiety having the three functional groups is phloroglucinol.

8. The process of claim acid anhydride includes an anhydride of anunsaturated dibasic acid, and the monoe'poxide is an alkylene oxide.

9. The process of claim is propylene oxide and the anhydride. isphthalic an: hydride.

It The process of claim 1 wherein the reaction of the initiator,monoepoxide and anhydride is carried out in the presence of a catalyst.

11. The process of claim 10 wherein the catalyst is a tertiary amine.

References Cited UNITED STATES PATENTS 3,089,863 5/1963 Hicks et a1.260-75 JOSEPH L. SCHOFER, Primary Examiner.

J. KIGHT, Assistant Examiner.

1 wherein the dicarboxylic 1 wherein the monoepoxide

1. IN THE PREPARATION OF THERMOPLASTIC POLYESTERS FROM DISCARBOXYLIC ACID ANHYDRIDES AND MONOEPOXIDES, THE PROCESS FOR PREPARING BRANCH CHAIN POLYESTERS HAVING END GROUPS WHICH DO NOT REACT WITH EACH OTHER DURING PREPARATION, COMPRISING A COMPOUND WHICH ACTS AS A REACTION INITIATOR WHICH IS A MONOMER, A POLYMER OR A COPOLYMER HAVING AT LEAST THREE FUNCTIONAL CONSTITUENTS OF THE GROUP CONSISTING OF CARBOXYL RADICALS, PHENOLIC RADICALS OR COMBINATIONS THEREOF, THE NUMBER OF SUCH GROUPS BEING EQUAL TO THE NUMBER OF BRANCH CHAINS DESIRED, REACTING THE INITIATOR, THE ANHYDRIDE AND THE MONOEPOXIDE BY HEATING THE REACTANTS AT AN ELEVATED TEMPERATURE BELOW 150*C. SUFFICIENT TO BRING ABOUT A REACTION OF THE ANHYDRIDE WITH THE ALCOHOLIC HYDROXYL GROUP FORMING CARBOXYL GROUPS, THE REACTION OF MONOEPOXIDE WITH THE PHENOLIC HYDROXYL GROUPS TO FORM ALCOHOLIC HYDROXYL GROUPS, AS WELL AS A REACTION OF MONOEPOXIDE WITH THE CARBOXYL GROUPS ALSO FORMING ALCOHOLIC HYDROXYL GROUPS AND MAINTAINING THE TEMPERATURE BELOW THAT AT WHICH THE CARBOXY-HYDROXY REACTION TAKES PLACE SO THAT END GROUPS OF POLYESTER CHAINS GROWING BY THE SUCCESSIVE ADDITION OF ANHYDRIDE AND MONOEPOXIDE TO THE INITIATOR, DO NOT REACT WITH EACH OTHER AND FORM WATER, SAID MONOEPOXIDE BEING FREE OF SUBSTITUENTS CAPABLE OF REACTING WITH AN ACID ANHYDRIDE. 